Consider the sentence:
He has gone.
This is one of the example auxiliary verb sentences from: "Radford, A. English syntax: An introduction, Cambridge University Press, 2004"
has is an auxiliary verb, gone is a normal verb.
Compare to the sentence:
He has a dog.
Here has is a normal verb.
I am wondering if seeing if two verb are in a row is a necessary and sufficient condition for the first to be an auxiliary?